print_terminal_palette.rs

const RESET: &str = "\x1b[m";

/// Print all the colours of the terminal to STDOUT.
fn print_native_palette() {
    println!("╭─────────────────╮");
    for y in 0u8..8 {
        print!("│");
        print_true_colour_full_bg(255, y, 0);
        print_true_colour_full_bg(0, 0, 255);
        for x in 0u8..15 {
            let background_colour = (y * 32) + x;
            let foreground_colour = background_colour + 16;
            print!("\x1b[48;5;{background_colour}m\x1b[38;5;{foreground_colour}m▄{RESET}");
        }
        print!("│");
        println!();
    }
    println!("╰─────────────────╯");
}

/// Prints a true colour that completely fills the terminal cell's background.
/// Used to help orient ourselves when parsing the palette screenshot.
fn print_true_colour_full_bg(red: u8, green: u8, blue: u8) {
    print!("\x1b[48;2;{red};{green};{blue}m ");
}

fn main() {
    print_native_palette();
}